Taphonomic Alterations

What are the three types of taphonomic alterations?

1.) Human alterations

• disarticulation

• burning

2.) Animal alterations

• carnivores

• rodents

• birds

3.) Natural alterations

• weathering

• root etching

Human alterations

• typically attempts to hide or alter evidence

• you can also have humans altering animal bones (ex. butchery)

• disarticulation

  • cuts

  • chop

  • saw

• burning

  • cracking

  • warping

  • distortion

Disarticulation — cuts

• slices

• can be V-shaped or U-shaped

Disarticulation — chops

• more abrupt

• see V-shaped cuts in bone

• perpendicular to bone shaft

Disarticulation — sawing

• pattern in bone depends on tooth pattern on bone

Disarticulation — butchery

• depending on the cut of meat, can see cut marks at joint, articular surfaces, or mid-shaft

Burning

• see cracking, warping, and distortion in bone

• carbonized or calcined

Burning — carbonized

bone is black or brown colored

Burning — calcined

bone is white or grey colored

Animal alterations:

• carnivores

  • canids, felids, ursids

• rodents

  • porcupines, rats, mice

• birds

  • owls, hawks

• ungulates

  • sheep, pig

Carnivores (dogs, cats, bears)

• puncture marks

• scraping and striations (not as consistent as rodents)

• “like a dog gnawing on a chew bone”

Rodents (porcupines, beavers, mice)

• see paired parallel marks on top and bottom of bone surfaces

• use bone and other materials to sharpen and keep incisors short

Birds (typically birds of prey such as raptors)

• bones can have acid etching from digestion

• breakage pattern is unique

• will see more skeletal parts represented

• get vomited out

Ungulates (ex. deer)

• gnaw on bones for minerals

• less of a consistent pattern than rodents

Natural alterations — weathering

• caused by long-term loss of moisture

• bone cracks along the structural lines

• becomes more vulnerable and breaks easier

• bone ultimately disintegrates

Natural alterations — root etching

• irregular lines

• U-shaped at cross section

Natural alterations — bleaching

• caused by UV light

• causes bone to change in color

• becomes dry (loss of moisture)

Natural alterations — staining

• caused by prolonged contact with soil or grasses

  • can also be stained by other materials (ex. copper)